In the past, whole blood transfusion was the mainstream of the blood transfusion technology, in which all the components of blood obtained by blood donation are transfused. Recently, as technologies have advanced, blood component transfusion is performed, in which the obtained blood is separated into components such as red blood cells, platelets, and plasma, and only the component necessary for a patient are transfused. The blood component transfusion makes it possible to reduce burdens or side effects on a patient's circulatory system and effectively use the donated blood.
The blood (whole blood) obtained by blood donation or a blood component prepared from the whole blood is separated through centrifugation into a plurality of layers. For instance, by centrifuging whole blood, the whole blood is separated into a light supernatant PPP (platelet poor plasma) fraction, a heavy precipitated CRC (concentrated red blood cells) fraction, and a buffy coat formed therebetween. By centrifuging the buffy coat, the buffy coat is separated into a supernatant component that contains platelets and leukocytes and a precipitated component that contains red blood cells. When the residual component remaining after removal of leukocytes and platelets from whole blood is centrifuged, the component is separated into a plasma layer which is the supernatant component and a red blood cell layer which is the precipitated component.
In order to separate whole blood into a plurality of blood components and put and preserve the blood components in a plurality of preservation bags, or in order to further separate a blood component prepared from whole blood into a plurality of blood components and put and preserve the blood components in a plurality of preservation bags, a blood bag system in which a plurality of bags are connected using a plurality of tubes has been used. In addition, in such a blood bag system, in order to perform a predetermined blood treatment by switching the communication state between the bags, a clamp is provided for closing and opening the flow path in the tube.
Known clamps extend in a substantially annular shape from one end to the other end, and the tube is inserted into a pair of facing through-holes in a substantially straight state. In this state, the flow path of the tube is closed by clamping the clamp and pressing the side surface of the tube with a pair of protrusion sections. An example of this clamp is described in Japanese Patent Publication No. 3971654.
In the aforementioned clamp, it is necessary to insert the tube into a pair of through-holes. For this reason, for example, it is necessary to insert the tube into a pair of the through-holes of the clamp in the course of manufacturing a blood bag system before a blood bag, a branching connector, and the like are connected to both ends of the tube. This work consumes time.
Since the tube has a substantially straight state while it is inserted into a pair of the through-holes, the clamp may easily move with respect to the tube before the flow path of the tube is closed. In particular, for example, when the tube is arranged to extend in a vertical direction, the clamp may move downward due to gravity, which may affect workability of blood treatment.